﻿using System;
using System.Runtime.CompilerServices;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;

// BASE
namespace BCryptNet.BenchMarks._3._2._1
{
    public class BaseLine
    {

        [Serializable]
        public class BcryptAuthenticationException : Exception
        {
            /// <inheritdoc />
            /// <summary>Default constructor. </summary>
            public BcryptAuthenticationException()
            {
            }

            /// <inheritdoc />
            /// <summary>Initializes a new instance of <see cref="T:BCrypt.Net.BcryptAuthenticationException" />.</summary>
            /// <param name="message">The message.</param>
            public BcryptAuthenticationException(string message)
                : base(message)
            {
            }

            /// <inheritdoc />
            /// <summary>Initializes a new instance of <see cref="T:BCrypt.Net.BcryptAuthenticationException" />.</summary>
            /// <param name="message">       The message.</param>
            /// <param name="innerException">The inner exception.</param>
            public BcryptAuthenticationException(string message, Exception innerException)
                : base(message, innerException)
            {
            }
        }

        public enum HashType
        {
            None = -1,
            SHA256 = 0,
            SHA384 = 1,
            SHA512 = 2,

            /// <summary>
            ///     Will hash key using SHA384 but will not Base64 encode it prior to Crypt
            /// </summary>
            Legacy384 = 3
        }

        public class SaltParseException : Exception
        {
            /// <summary>Default constructor. </summary>
            public SaltParseException()
            {
            }

            /// <summary>Initializes a new instance of <see cref="SaltParseException" />.</summary>
            /// <param name="message">The message.</param>
            public SaltParseException(string message)
                : base(message)
            {
            }

            /// <summary>Initializes a new instance of <see cref="SaltParseException" />.</summary>
            /// <param name="message">       The message.</param>
            /// <param name="innerException">The inner exception.</param>
            public SaltParseException(string message, Exception innerException)
                : base(message, innerException)
            {
            }
        }

        [Serializable]
        public sealed class HashInformationException : Exception
        {
            /// <summary>
            ///     Default Constructor
            /// </summary>
            public HashInformationException()
            {
            }

            /// <summary>
            ///     Initializes a new instance of <see cref="HashInformationException" />.
            /// </summary>
            /// <param name="message"></param>
            public HashInformationException(string message) : base(message)
            {
            }

            /// <summary>
            ///     Initializes a new instance of <see cref="HashInformationException" />.
            /// </summary>
            /// <param name="message"></param>
            /// <param name="innerException"></param>
            public HashInformationException(string message, Exception innerException) : base(message, innerException)
            {
            }
        }

        public sealed class HashInformation
        {
            /// <summary>Constructor. </summary>
            /// <param name="settings">The message.</param>
            /// <param name="version">The message.</param>
            /// <param name="workFactor">The message.</param>
            /// <param name="rawHash">The message.</param>
            internal HashInformation(string settings, string version, string workFactor, string rawHash)
            {
                Settings = settings;
                Version = version;
                WorkFactor = workFactor;
                RawHash = rawHash;
            }

            /// <summary>
            ///     Settings string
            /// </summary>
            public string Settings { get; private set; }

            /// <summary>
            ///     Hash Version
            /// </summary>
            public string Version { get; private set; }

            /// <summary>
            ///     log rounds used / workfactor
            /// </summary>
            public string WorkFactor { get; private set; }

            /// <summary>
            ///     Raw Hash
            /// </summary>
            public string RawHash { get; private set; }
        }


        /// <summary>BCrypt implementation.</summary>
        /// <remarks>
        ///     <para>
        ///         BCrypt implements OpenBSD-style Blowfish password hashing using the scheme described in
        ///         <a href="http://www.usenix.org/event/usenix99/provos/provos_html/index.html">
        ///             "A Future-
        ///             Adaptable Password Scheme"
        ///         </a>
        ///         by Niels Provos and David Mazieres.
        ///     </para>
        ///     <para>
        ///         This password hashing system tries to thwart off-line password cracking using a
        ///         computationally-intensive hashing algorithm, based on Bruce Schneier's Blowfish cipher.
        ///         The work factor of the algorithm is parameterised, so it can be increased as computers
        ///         get faster.
        ///     </para>
        ///     <para>
        ///         To hash a password using the defaults, call the <see cref="BCrypt.HashPassword(string)" /> (which will generate
        ///         a random salt and hash at default cost), like this:
        ///     </para>
        ///     <code>string pw_hash = BCrypt.HashPassword(plain_password);</code>
        ///     <para>
        ///         To hash a password using SHA384 pre-hashing for increased entropy call
        ///         <see cref="BCrypt.EnhancedHashPassword(string)" />
        ///         (which will generate a random salt and hash at default cost), like this:
        ///     </para>
        ///     <code>string pw_hash = BCrypt.EnhancedHashPassword(plain_password);</code>
        ///     <para>
        ///         To check whether a plaintext password matches one that has been hashed previously,
        ///         use the <see cref="BCrypt.Verify(string, string, bool, HashType)" /> method:
        ///         (To validate an enhanced hash you can pass true as the last parameter of Verify or use
        ///         <see cref="BCrypt.EnhancedVerify(string, string, HashType)" />)
        ///     </para>
        ///     <code>
        ///     if (BCrypt.Verify(candidate_password, stored_hash))
        ///         Console.WriteLine("It matches");
        ///     else
        ///         Console.WriteLine("It does not match");
        ///   </code>
        ///     <para>
        ///         The <see cref="GenerateSalt()" /> method takes an optional parameter (workFactor) that
        ///         determines the computational complexity of the hashing:
        ///     </para>
        ///     <code>
        ///     string strong_salt = BCrypt.GenerateSalt(10);
        ///     string stronger_salt = BCrypt.GenerateSalt(12);
        ///   </code>
        ///     <para>
        ///         The amount of work increases exponentially (2^workFactor), so each increment is twice
        ///         as much work. The default workFactor is 10, and the valid range is 4 to 31.
        ///     </para>
        /// </remarks>
        public sealed class BCrypt
        {
            // BCrypt parameters
            /// <summary>
            ///     Default Work Factor
            /// </summary>
            private const int DefaultRounds = 11;

            private const int BCryptSaltLen = 128 / 8; // 128 bits

            private static readonly Encoding SafeUTF8 =
                new UTF8Encoding(encoderShouldEmitUTF8Identifier: false, throwOnInvalidBytes: true);

            private const HashType DefaultEnhancedHashType = HashType.SHA384;

            // Blowfish parameters
            private const int BlowfishNumRounds = 16;

            /// <summary>
            ///     RandomNumberGenerator.Create calls
            ///     RandomNumberGenerator.Create("System.Security.Cryptography.RandomNumberGenerator"), which will create an instance
            ///     of RNGCryptoServiceProvider.
            ///     https://msdn.microsoft.com/en-us/library/42ks8fz1
            /// </summary>
            private static readonly RandomNumberGenerator RngCsp = RandomNumberGenerator.Create(); // secure PRNG

            #region Initial contents of key schedule

            private static readonly uint[] POrig =
            {
                0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344, 0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
                0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c, 0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917,
                0x9216d5d9, 0x8979fb1b
            };

            private static readonly uint[] SOrig =
            {
                0xd1310ba6, 0x98dfb5ac, 0x2ffd72db, 0xd01adfb7, 0xb8e1afed, 0x6a267e96, 0xba7c9045, 0xf12c7f99,
                0x24a19947, 0xb3916cf7, 0x0801f2e2, 0x858efc16, 0x636920d8, 0x71574e69, 0xa458fea3, 0xf4933d7e,
                0x0d95748f, 0x728eb658, 0x718bcd58, 0x82154aee, 0x7b54a41d, 0xc25a59b5, 0x9c30d539, 0x2af26013,
                0xc5d1b023, 0x286085f0, 0xca417918, 0xb8db38ef, 0x8e79dcb0, 0x603a180e, 0x6c9e0e8b, 0xb01e8a3e,
                0xd71577c1, 0xbd314b27, 0x78af2fda, 0x55605c60, 0xe65525f3, 0xaa55ab94, 0x57489862, 0x63e81440,
                0x55ca396a, 0x2aab10b6, 0xb4cc5c34, 0x1141e8ce, 0xa15486af, 0x7c72e993, 0xb3ee1411, 0x636fbc2a,
                0x2ba9c55d, 0x741831f6, 0xce5c3e16, 0x9b87931e, 0xafd6ba33, 0x6c24cf5c, 0x7a325381, 0x28958677,
                0x3b8f4898, 0x6b4bb9af, 0xc4bfe81b, 0x66282193, 0x61d809cc, 0xfb21a991, 0x487cac60, 0x5dec8032,
                0xef845d5d, 0xe98575b1, 0xdc262302, 0xeb651b88, 0x23893e81, 0xd396acc5, 0x0f6d6ff3, 0x83f44239,
                0x2e0b4482, 0xa4842004, 0x69c8f04a, 0x9e1f9b5e, 0x21c66842, 0xf6e96c9a, 0x670c9c61, 0xabd388f0,
                0x6a51a0d2, 0xd8542f68, 0x960fa728, 0xab5133a3, 0x6eef0b6c, 0x137a3be4, 0xba3bf050, 0x7efb2a98,
                0xa1f1651d, 0x39af0176, 0x66ca593e, 0x82430e88, 0x8cee8619, 0x456f9fb4, 0x7d84a5c3, 0x3b8b5ebe,
                0xe06f75d8, 0x85c12073, 0x401a449f, 0x56c16aa6, 0x4ed3aa62, 0x363f7706, 0x1bfedf72, 0x429b023d,
                0x37d0d724, 0xd00a1248, 0xdb0fead3, 0x49f1c09b, 0x075372c9, 0x80991b7b, 0x25d479d8, 0xf6e8def7,
                0xe3fe501a, 0xb6794c3b, 0x976ce0bd, 0x04c006ba, 0xc1a94fb6, 0x409f60c4, 0x5e5c9ec2, 0x196a2463,
                0x68fb6faf, 0x3e6c53b5, 0x1339b2eb, 0x3b52ec6f, 0x6dfc511f, 0x9b30952c, 0xcc814544, 0xaf5ebd09,
                0xbee3d004, 0xde334afd, 0x660f2807, 0x192e4bb3, 0xc0cba857, 0x45c8740f, 0xd20b5f39, 0xb9d3fbdb,
                0x5579c0bd, 0x1a60320a, 0xd6a100c6, 0x402c7279, 0x679f25fe, 0xfb1fa3cc, 0x8ea5e9f8, 0xdb3222f8,
                0x3c7516df, 0xfd616b15, 0x2f501ec8, 0xad0552ab, 0x323db5fa, 0xfd238760, 0x53317b48, 0x3e00df82,
                0x9e5c57bb, 0xca6f8ca0, 0x1a87562e, 0xdf1769db, 0xd542a8f6, 0x287effc3, 0xac6732c6, 0x8c4f5573,
                0x695b27b0, 0xbbca58c8, 0xe1ffa35d, 0xb8f011a0, 0x10fa3d98, 0xfd2183b8, 0x4afcb56c, 0x2dd1d35b,
                0x9a53e479, 0xb6f84565, 0xd28e49bc, 0x4bfb9790, 0xe1ddf2da, 0xa4cb7e33, 0x62fb1341, 0xcee4c6e8,
                0xef20cada, 0x36774c01, 0xd07e9efe, 0x2bf11fb4, 0x95dbda4d, 0xae909198, 0xeaad8e71, 0x6b93d5a0,
                0xd08ed1d0, 0xafc725e0, 0x8e3c5b2f, 0x8e7594b7, 0x8ff6e2fb, 0xf2122b64, 0x8888b812, 0x900df01c,
                0x4fad5ea0, 0x688fc31c, 0xd1cff191, 0xb3a8c1ad, 0x2f2f2218, 0xbe0e1777, 0xea752dfe, 0x8b021fa1,
                0xe5a0cc0f, 0xb56f74e8, 0x18acf3d6, 0xce89e299, 0xb4a84fe0, 0xfd13e0b7, 0x7cc43b81, 0xd2ada8d9,
                0x165fa266, 0x80957705, 0x93cc7314, 0x211a1477, 0xe6ad2065, 0x77b5fa86, 0xc75442f5, 0xfb9d35cf,
                0xebcdaf0c, 0x7b3e89a0, 0xd6411bd3, 0xae1e7e49, 0x00250e2d, 0x2071b35e, 0x226800bb, 0x57b8e0af,
                0x2464369b, 0xf009b91e, 0x5563911d, 0x59dfa6aa, 0x78c14389, 0xd95a537f, 0x207d5ba2, 0x02e5b9c5,
                0x83260376, 0x6295cfa9, 0x11c81968, 0x4e734a41, 0xb3472dca, 0x7b14a94a, 0x1b510052, 0x9a532915,
                0xd60f573f, 0xbc9bc6e4, 0x2b60a476, 0x81e67400, 0x08ba6fb5, 0x571be91f, 0xf296ec6b, 0x2a0dd915,
                0xb6636521, 0xe7b9f9b6, 0xff34052e, 0xc5855664, 0x53b02d5d, 0xa99f8fa1, 0x08ba4799, 0x6e85076a,
                0x4b7a70e9, 0xb5b32944, 0xdb75092e, 0xc4192623, 0xad6ea6b0, 0x49a7df7d, 0x9cee60b8, 0x8fedb266,
                0xecaa8c71, 0x699a17ff, 0x5664526c, 0xc2b19ee1, 0x193602a5, 0x75094c29, 0xa0591340, 0xe4183a3e,
                0x3f54989a, 0x5b429d65, 0x6b8fe4d6, 0x99f73fd6, 0xa1d29c07, 0xefe830f5, 0x4d2d38e6, 0xf0255dc1,
                0x4cdd2086, 0x8470eb26, 0x6382e9c6, 0x021ecc5e, 0x09686b3f, 0x3ebaefc9, 0x3c971814, 0x6b6a70a1,
                0x687f3584, 0x52a0e286, 0xb79c5305, 0xaa500737, 0x3e07841c, 0x7fdeae5c, 0x8e7d44ec, 0x5716f2b8,
                0xb03ada37, 0xf0500c0d, 0xf01c1f04, 0x0200b3ff, 0xae0cf51a, 0x3cb574b2, 0x25837a58, 0xdc0921bd,
                0xd19113f9, 0x7ca92ff6, 0x94324773, 0x22f54701, 0x3ae5e581, 0x37c2dadc, 0xc8b57634, 0x9af3dda7,
                0xa9446146, 0x0fd0030e, 0xecc8c73e, 0xa4751e41, 0xe238cd99, 0x3bea0e2f, 0x3280bba1, 0x183eb331,
                0x4e548b38, 0x4f6db908, 0x6f420d03, 0xf60a04bf, 0x2cb81290, 0x24977c79, 0x5679b072, 0xbcaf89af,
                0xde9a771f, 0xd9930810, 0xb38bae12, 0xdccf3f2e, 0x5512721f, 0x2e6b7124, 0x501adde6, 0x9f84cd87,
                0x7a584718, 0x7408da17, 0xbc9f9abc, 0xe94b7d8c, 0xec7aec3a, 0xdb851dfa, 0x63094366, 0xc464c3d2,
                0xef1c1847, 0x3215d908, 0xdd433b37, 0x24c2ba16, 0x12a14d43, 0x2a65c451, 0x50940002, 0x133ae4dd,
                0x71dff89e, 0x10314e55, 0x81ac77d6, 0x5f11199b, 0x043556f1, 0xd7a3c76b, 0x3c11183b, 0x5924a509,
                0xf28fe6ed, 0x97f1fbfa, 0x9ebabf2c, 0x1e153c6e, 0x86e34570, 0xeae96fb1, 0x860e5e0a, 0x5a3e2ab3,
                0x771fe71c, 0x4e3d06fa, 0x2965dcb9, 0x99e71d0f, 0x803e89d6, 0x5266c825, 0x2e4cc978, 0x9c10b36a,
                0xc6150eba, 0x94e2ea78, 0xa5fc3c53, 0x1e0a2df4, 0xf2f74ea7, 0x361d2b3d, 0x1939260f, 0x19c27960,
                0x5223a708, 0xf71312b6, 0xebadfe6e, 0xeac31f66, 0xe3bc4595, 0xa67bc883, 0xb17f37d1, 0x018cff28,
                0xc332ddef, 0xbe6c5aa5, 0x65582185, 0x68ab9802, 0xeecea50f, 0xdb2f953b, 0x2aef7dad, 0x5b6e2f84,
                0x1521b628, 0x29076170, 0xecdd4775, 0x619f1510, 0x13cca830, 0xeb61bd96, 0x0334fe1e, 0xaa0363cf,
                0xb5735c90, 0x4c70a239, 0xd59e9e0b, 0xcbaade14, 0xeecc86bc, 0x60622ca7, 0x9cab5cab, 0xb2f3846e,
                0x648b1eaf, 0x19bdf0ca, 0xa02369b9, 0x655abb50, 0x40685a32, 0x3c2ab4b3, 0x319ee9d5, 0xc021b8f7,
                0x9b540b19, 0x875fa099, 0x95f7997e, 0x623d7da8, 0xf837889a, 0x97e32d77, 0x11ed935f, 0x16681281,
                0x0e358829, 0xc7e61fd6, 0x96dedfa1, 0x7858ba99, 0x57f584a5, 0x1b227263, 0x9b83c3ff, 0x1ac24696,
                0xcdb30aeb, 0x532e3054, 0x8fd948e4, 0x6dbc3128, 0x58ebf2ef, 0x34c6ffea, 0xfe28ed61, 0xee7c3c73,
                0x5d4a14d9, 0xe864b7e3, 0x42105d14, 0x203e13e0, 0x45eee2b6, 0xa3aaabea, 0xdb6c4f15, 0xfacb4fd0,
                0xc742f442, 0xef6abbb5, 0x654f3b1d, 0x41cd2105, 0xd81e799e, 0x86854dc7, 0xe44b476a, 0x3d816250,
                0xcf62a1f2, 0x5b8d2646, 0xfc8883a0, 0xc1c7b6a3, 0x7f1524c3, 0x69cb7492, 0x47848a0b, 0x5692b285,
                0x095bbf00, 0xad19489d, 0x1462b174, 0x23820e00, 0x58428d2a, 0x0c55f5ea, 0x1dadf43e, 0x233f7061,
                0x3372f092, 0x8d937e41, 0xd65fecf1, 0x6c223bdb, 0x7cde3759, 0xcbee7460, 0x4085f2a7, 0xce77326e,
                0xa6078084, 0x19f8509e, 0xe8efd855, 0x61d99735, 0xa969a7aa, 0xc50c06c2, 0x5a04abfc, 0x800bcadc,
                0x9e447a2e, 0xc3453484, 0xfdd56705, 0x0e1e9ec9, 0xdb73dbd3, 0x105588cd, 0x675fda79, 0xe3674340,
                0xc5c43465, 0x713e38d8, 0x3d28f89e, 0xf16dff20, 0x153e21e7, 0x8fb03d4a, 0xe6e39f2b, 0xdb83adf7,
                0xe93d5a68, 0x948140f7, 0xf64c261c, 0x94692934, 0x411520f7, 0x7602d4f7, 0xbcf46b2e, 0xd4a20068,
                0xd4082471, 0x3320f46a, 0x43b7d4b7, 0x500061af, 0x1e39f62e, 0x97244546, 0x14214f74, 0xbf8b8840,
                0x4d95fc1d, 0x96b591af, 0x70f4ddd3, 0x66a02f45, 0xbfbc09ec, 0x03bd9785, 0x7fac6dd0, 0x31cb8504,
                0x96eb27b3, 0x55fd3941, 0xda2547e6, 0xabca0a9a, 0x28507825, 0x530429f4, 0x0a2c86da, 0xe9b66dfb,
                0x68dc1462, 0xd7486900, 0x680ec0a4, 0x27a18dee, 0x4f3ffea2, 0xe887ad8c, 0xb58ce006, 0x7af4d6b6,
                0xaace1e7c, 0xd3375fec, 0xce78a399, 0x406b2a42, 0x20fe9e35, 0xd9f385b9, 0xee39d7ab, 0x3b124e8b,
                0x1dc9faf7, 0x4b6d1856, 0x26a36631, 0xeae397b2, 0x3a6efa74, 0xdd5b4332, 0x6841e7f7, 0xca7820fb,
                0xfb0af54e, 0xd8feb397, 0x454056ac, 0xba489527, 0x55533a3a, 0x20838d87, 0xfe6ba9b7, 0xd096954b,
                0x55a867bc, 0xa1159a58, 0xcca92963, 0x99e1db33, 0xa62a4a56, 0x3f3125f9, 0x5ef47e1c, 0x9029317c,
                0xfdf8e802, 0x04272f70, 0x80bb155c, 0x05282ce3, 0x95c11548, 0xe4c66d22, 0x48c1133f, 0xc70f86dc,
                0x07f9c9ee, 0x41041f0f, 0x404779a4, 0x5d886e17, 0x325f51eb, 0xd59bc0d1, 0xf2bcc18f, 0x41113564,
                0x257b7834, 0x602a9c60, 0xdff8e8a3, 0x1f636c1b, 0x0e12b4c2, 0x02e1329e, 0xaf664fd1, 0xcad18115,
                0x6b2395e0, 0x333e92e1, 0x3b240b62, 0xeebeb922, 0x85b2a20e, 0xe6ba0d99, 0xde720c8c, 0x2da2f728,
                0xd0127845, 0x95b794fd, 0x647d0862, 0xe7ccf5f0, 0x5449a36f, 0x877d48fa, 0xc39dfd27, 0xf33e8d1e,
                0x0a476341, 0x992eff74, 0x3a6f6eab, 0xf4f8fd37, 0xa812dc60, 0xa1ebddf8, 0x991be14c, 0xdb6e6b0d,
                0xc67b5510, 0x6d672c37, 0x2765d43b, 0xdcd0e804, 0xf1290dc7, 0xcc00ffa3, 0xb5390f92, 0x690fed0b,
                0x667b9ffb, 0xcedb7d9c, 0xa091cf0b, 0xd9155ea3, 0xbb132f88, 0x515bad24, 0x7b9479bf, 0x763bd6eb,
                0x37392eb3, 0xcc115979, 0x8026e297, 0xf42e312d, 0x6842ada7, 0xc66a2b3b, 0x12754ccc, 0x782ef11c,
                0x6a124237, 0xb79251e7, 0x06a1bbe6, 0x4bfb6350, 0x1a6b1018, 0x11caedfa, 0x3d25bdd8, 0xe2e1c3c9,
                0x44421659, 0x0a121386, 0xd90cec6e, 0xd5abea2a, 0x64af674e, 0xda86a85f, 0xbebfe988, 0x64e4c3fe,
                0x9dbc8057, 0xf0f7c086, 0x60787bf8, 0x6003604d, 0xd1fd8346, 0xf6381fb0, 0x7745ae04, 0xd736fccc,
                0x83426b33, 0xf01eab71, 0xb0804187, 0x3c005e5f, 0x77a057be, 0xbde8ae24, 0x55464299, 0xbf582e61,
                0x4e58f48f, 0xf2ddfda2, 0xf474ef38, 0x8789bdc2, 0x5366f9c3, 0xc8b38e74, 0xb475f255, 0x46fcd9b9,
                0x7aeb2661, 0x8b1ddf84, 0x846a0e79, 0x915f95e2, 0x466e598e, 0x20b45770, 0x8cd55591, 0xc902de4c,
                0xb90bace1, 0xbb8205d0, 0x11a86248, 0x7574a99e, 0xb77f19b6, 0xe0a9dc09, 0x662d09a1, 0xc4324633,
                0xe85a1f02, 0x09f0be8c, 0x4a99a025, 0x1d6efe10, 0x1ab93d1d, 0x0ba5a4df, 0xa186f20f, 0x2868f169,
                0xdcb7da83, 0x573906fe, 0xa1e2ce9b, 0x4fcd7f52, 0x50115e01, 0xa70683fa, 0xa002b5c4, 0x0de6d027,
                0x9af88c27, 0x773f8641, 0xc3604c06, 0x61a806b5, 0xf0177a28, 0xc0f586e0, 0x006058aa, 0x30dc7d62,
                0x11e69ed7, 0x2338ea63, 0x53c2dd94, 0xc2c21634, 0xbbcbee56, 0x90bcb6de, 0xebfc7da1, 0xce591d76,
                0x6f05e409, 0x4b7c0188, 0x39720a3d, 0x7c927c24, 0x86e3725f, 0x724d9db9, 0x1ac15bb4, 0xd39eb8fc,
                0xed545578, 0x08fca5b5, 0xd83d7cd3, 0x4dad0fc4, 0x1e50ef5e, 0xb161e6f8, 0xa28514d9, 0x6c51133c,
                0x6fd5c7e7, 0x56e14ec4, 0x362abfce, 0xddc6c837, 0xd79a3234, 0x92638212, 0x670efa8e, 0x406000e0,
                0x3a39ce37, 0xd3faf5cf, 0xabc27737, 0x5ac52d1b, 0x5cb0679e, 0x4fa33742, 0xd3822740, 0x99bc9bbe,
                0xd5118e9d, 0xbf0f7315, 0xd62d1c7e, 0xc700c47b, 0xb78c1b6b, 0x21a19045, 0xb26eb1be, 0x6a366eb4,
                0x5748ab2f, 0xbc946e79, 0xc6a376d2, 0x6549c2c8, 0x530ff8ee, 0x468dde7d, 0xd5730a1d, 0x4cd04dc6,
                0x2939bbdb, 0xa9ba4650, 0xac9526e8, 0xbe5ee304, 0xa1fad5f0, 0x6a2d519a, 0x63ef8ce2, 0x9a86ee22,
                0xc089c2b8, 0x43242ef6, 0xa51e03aa, 0x9cf2d0a4, 0x83c061ba, 0x9be96a4d, 0x8fe51550, 0xba645bd6,
                0x2826a2f9, 0xa73a3ae1, 0x4ba99586, 0xef5562e9, 0xc72fefd3, 0xf752f7da, 0x3f046f69, 0x77fa0a59,
                0x80e4a915, 0x87b08601, 0x9b09e6ad, 0x3b3ee593, 0xe990fd5a, 0x9e34d797, 0x2cf0b7d9, 0x022b8b51,
                0x96d5ac3a, 0x017da67d, 0xd1cf3ed6, 0x7c7d2d28, 0x1f9f25cf, 0xadf2b89b, 0x5ad6b472, 0x5a88f54c,
                0xe029ac71, 0xe019a5e6, 0x47b0acfd, 0xed93fa9b, 0xe8d3c48d, 0x283b57cc, 0xf8d56629, 0x79132e28,
                0x785f0191, 0xed756055, 0xf7960e44, 0xe3d35e8c, 0x15056dd4, 0x88f46dba, 0x03a16125, 0x0564f0bd,
                0xc3eb9e15, 0x3c9057a2, 0x97271aec, 0xa93a072a, 0x1b3f6d9b, 0x1e6321f5, 0xf59c66fb, 0x26dcf319,
                0x7533d928, 0xb155fdf5, 0x03563482, 0x8aba3cbb, 0x28517711, 0xc20ad9f8, 0xabcc5167, 0xccad925f,
                0x4de81751, 0x3830dc8e, 0x379d5862, 0x9320f991, 0xea7a90c2, 0xfb3e7bce, 0x5121ce64, 0x774fbe32,
                0xa8b6e37e, 0xc3293d46, 0x48de5369, 0x6413e680, 0xa2ae0810, 0xdd6db224, 0x69852dfd, 0x09072166,
                0xb39a460a, 0x6445c0dd, 0x586cdecf, 0x1c20c8ae, 0x5bbef7dd, 0x1b588d40, 0xccd2017f, 0x6bb4e3bb,
                0xdda26a7e, 0x3a59ff45, 0x3e350a44, 0xbcb4cdd5, 0x72eacea8, 0xfa6484bb, 0x8d6612ae, 0xbf3c6f47,
                0xd29be463, 0x542f5d9e, 0xaec2771b, 0xf64e6370, 0x740e0d8d, 0xe75b1357, 0xf8721671, 0xaf537d5d,
                0x4040cb08, 0x4eb4e2cc, 0x34d2466a, 0x0115af84, 0xe1b00428, 0x95983a1d, 0x06b89fb4, 0xce6ea048,
                0x6f3f3b82, 0x3520ab82, 0x011a1d4b, 0x277227f8, 0x611560b1, 0xe7933fdc, 0xbb3a792b, 0x344525bd,
                0xa08839e1, 0x51ce794b, 0x2f32c9b7, 0xa01fbac9, 0xe01cc87e, 0xbcc7d1f6, 0xcf0111c3, 0xa1e8aac7,
                0x1a908749, 0xd44fbd9a, 0xd0dadecb, 0xd50ada38, 0x0339c32a, 0xc6913667, 0x8df9317c, 0xe0b12b4f,
                0xf79e59b7, 0x43f5bb3a, 0xf2d519ff, 0x27d9459c, 0xbf97222c, 0x15e6fc2a, 0x0f91fc71, 0x9b941525,
                0xfae59361, 0xceb69ceb, 0xc2a86459, 0x12baa8d1, 0xb6c1075e, 0xe3056a0c, 0x10d25065, 0xcb03a442,
                0xe0ec6e0e, 0x1698db3b, 0x4c98a0be, 0x3278e964, 0x9f1f9532, 0xe0d392df, 0xd3a0342b, 0x8971f21e,
                0x1b0a7441, 0x4ba3348c, 0xc5be7120, 0xc37632d8, 0xdf359f8d, 0x9b992f2e, 0xe60b6f47, 0x0fe3f11d,
                0xe54cda54, 0x1edad891, 0xce6279cf, 0xcd3e7e6f, 0x1618b166, 0xfd2c1d05, 0x848fd2c5, 0xf6fb2299,
                0xf523f357, 0xa6327623, 0x93a83531, 0x56cccd02, 0xacf08162, 0x5a75ebb5, 0x6e163697, 0x88d273cc,
                0xde966292, 0x81b949d0, 0x4c50901b, 0x71c65614, 0xe6c6c7bd, 0x327a140a, 0x45e1d006, 0xc3f27b9a,
                0xc9aa53fd, 0x62a80f00, 0xbb25bfe2, 0x35bdd2f6, 0x71126905, 0xb2040222, 0xb6cbcf7c, 0xcd769c2b,
                0x53113ec0, 0x1640e3d3, 0x38abbd60, 0x2547adf0, 0xba38209c, 0xf746ce76, 0x77afa1c5, 0x20756060,
                0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e, 0x1948c25c, 0x02fb8a8c, 0x01c36ae4, 0xd6ebe1f9,
                0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f, 0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6
            };

            #endregion Initial contents of key schedule

            // BCrypt IV: "OrpheanBeholderScryDoubt"
            private static readonly uint[] BfCryptCiphertext =
            {
                0x4f727068, 0x65616e42, 0x65686f6c, 0x64657253, 0x63727944, 0x6f756274
            };

            // Table for Base64 encoding
            private static readonly char[] Base64Code =
            {
                '.', '/', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
                'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8',
                '9'
            };

            // Table for Base64 decoding
            private static readonly int[] Index64 =
            {
                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
                -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 54, 55, 56, 57,
                58, 59, 60, 61, 62, 63, -1, -1, -1, -1, -1, -1, -1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
                17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, -1, -1, -1, -1, -1, -1, 28, 29, 30, 31, 32, 33, 34, 35, 36,
                37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, -1, -1, -1, -1, -1
            };

            // Fixed configuration
            private const string EmptyString = "";
            private const char DefaultHashVersion = 'a';
            private const string Nul = "\0";
            private const short MinRounds = 4;
            private const short MaxRounds = 31;


            // Expanded Blowfish key
            private uint[] _p;
            private uint[] _s;


            /// <summary>
            ///     Validate existing hash and password,
            /// </summary>
            /// <param name="currentKey">Current password / string</param>
            /// <param name="currentHash">Current hash to validate password against</param>
            /// <param name="newKey">NEW password / string to be hashed</param>
            /// <param name="workFactor">
            ///     The log2 of the number of rounds of hashing to apply - the work
            ///     factor therefore increases as 2^workFactor. Default is 11
            /// </param>
            /// <param name="forceWorkFactor">
            ///     By default this method will not accept a work factor lower
            ///     than the one set in the current hash and will set the new work-factor to match.
            /// </param>
            /// <exception cref="BcryptAuthenticationException">returned if the users hash and current pass doesn't validate</exception>
            /// <exception cref="SaltParseException">returned if the salt is invalid in any way</exception>
            /// <exception cref="ArgumentException">returned if the hash is invalid</exception>
            /// <exception cref="ArgumentNullException">returned if the user hash is null</exception>
            /// <returns>New hash of new password</returns>
            public static string ValidateAndReplacePassword(string currentKey, string currentHash, string newKey,
                int workFactor = DefaultRounds, bool forceWorkFactor = false) =>
                ValidateAndReplacePassword(currentKey, currentHash, false, HashType.None, newKey, false, HashType.None,
                    workFactor, forceWorkFactor);


            /// <summary>
            ///     Validate existing hash and password,
            /// </summary>
            /// <param name="currentKey">Current password / string</param>
            /// <param name="currentHash">Current hash to validate password against</param>
            /// <param name="currentKeyEnhancedEntropy">
            ///     Set to true,the string will undergo SHA384 hashing to make
            ///     use of available entropy prior to bcrypt hashing
            /// </param>
            /// <param name="oldHashType">HashType used (default SHA384)</param>
            /// <param name="newKey">NEW password / string to be hashed</param>
            /// <param name="newKeyEnhancedEntropy">
            ///     Set to true,the string will undergo SHA384 hashing to make
            ///     use of available entropy prior to bcrypt hashing
            /// </param>
            /// <param name="newHashType">HashType to use (default SHA384)</param>
            /// <param name="workFactor">
            ///     The log2 of the number of rounds of hashing to apply - the work
            ///     factor therefore increases as 2^workFactor. Default is 11
            /// </param>
            /// <param name="forceWorkFactor">
            ///     By default this method will not accept a work factor lower
            ///     than the one set in the current hash and will set the new work-factor to match.
            /// </param>
            /// <exception cref="BcryptAuthenticationException">returned if the users hash and current pass doesn't validate</exception>
            /// <exception cref="SaltParseException">returned if the salt is invalid in any way</exception>
            /// <exception cref="ArgumentException">returned if the hash is invalid</exception>
            /// <exception cref="ArgumentNullException">returned if the user hash is null</exception>
            /// <returns>New hash of new password</returns>
            public static string ValidateAndReplacePassword(string currentKey, string currentHash,
                bool currentKeyEnhancedEntropy, HashType oldHashType,
                string newKey, bool newKeyEnhancedEntropy = false, HashType newHashType = DefaultEnhancedHashType,
                int workFactor = DefaultRounds, bool forceWorkFactor = false)
            {
                if (currentKey == null)
                {
                    throw new ArgumentNullException(nameof(currentKey));
                }

                if (string.IsNullOrEmpty(currentHash))
                {
                    throw new ArgumentException("Invalid Hash", nameof(currentHash));
                }

                if (Verify(currentKey, currentHash, currentKeyEnhancedEntropy, oldHashType))
                {
                    // Determine the starting offset and validate the salt
                    int startingOffset;

                    if (currentHash[0] != '$' || currentHash[1] != '2')
                    {
                        throw new SaltParseException("Invalid bcrypt version");
                    }

                    if (currentHash[2] == '$')
                    {
                        startingOffset = 3;
                    }
                    else
                    {
                        char minor = currentHash[2];
                        if (minor != 'a' && minor != 'b' && minor != 'x' && minor != 'y' || currentHash[3] != '$')
                        {
                            throw new SaltParseException("Invalid bcrypt revision");
                        }

                        startingOffset = 4;
                    }

                    // Extract number of rounds
                    if (currentHash[startingOffset + 2] > '$')
                    {
                        throw new SaltParseException("Missing work factor");
                    }

                    // Extract details from salt
                    int currentWorkFactor = Convert.ToInt16(currentHash.Substring(startingOffset, 2));

                    // Throw if log rounds are out of range on hash, deals with custom salts
                    if (workFactor < 1 || workFactor > 31)
                    {
                        throw new SaltParseException("Work factor out of range");
                    }

                    // Never downgrade workfactor (unless forced)
                    if (!forceWorkFactor && currentWorkFactor > workFactor)
                    {
                        workFactor = currentWorkFactor;
                    }

                    return HashPassword(newKey, GenerateSalt(workFactor), newKeyEnhancedEntropy, newHashType);
                }

                throw new BcryptAuthenticationException("Current credentials could not be authenticated");
            }

            /// <summary>
            ///     Hash a string using the OpenBSD BCrypt scheme and a salt generated by <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <remarks>Just an alias for HashPassword.</remarks>
            /// <param name="inputKey">  The string to hash.</param>
            /// <param name="workFactor">
            ///     The log2 of the number of rounds of hashing to apply - the work
            ///     factor therefore increases as 2^workFactor. Default is 11
            /// </param>
            /// <returns>The hashed string.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            [Obsolete("Replace with HashPassword, this method will be removed at a later date")]
            public static string HashString(string inputKey, int workFactor = DefaultRounds) =>
                HashPassword(inputKey, GenerateSalt(workFactor));

            /// <summary>
            ///     Hash a password using the OpenBSD BCrypt scheme and a salt generated by <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <param name="inputKey">The password to hash.</param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string HashPassword(string inputKey) => HashPassword(inputKey, GenerateSalt());

            /// <summary>
            ///     Pre-hash a password with SHA384 then using the OpenBSD BCrypt scheme and a salt generated by
            ///     <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <param name="inputKey">The password to hash.</param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string EnhancedHashPassword(string inputKey) => HashPassword(inputKey, GenerateSalt(), true);

            /// <summary>
            ///     Pre-hash a password with SHA384 then using the OpenBSD BCrypt scheme and a salt generated by
            ///     <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <param name="inputKey">The password to hash.</param>
            /// <param name="workFactor"></param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string EnhancedHashPassword(string inputKey, int workFactor) =>
                HashPassword(inputKey, GenerateSalt(workFactor), true);

            /// <summary>
            ///     Pre-hash a password with SHA384 then using the OpenBSD BCrypt scheme and a salt generated by
            ///     <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <param name="inputKey">The password to hash.</param>
            /// <param name="workFactor"></param>
            /// <param name="hashType">Configurable hash type for enhanced entropy</param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string EnhancedHashPassword(string inputKey, int workFactor, HashType hashType) =>
                HashPassword(inputKey, GenerateSalt(workFactor), true, hashType);


            /// <summary>
            ///     Pre-hash a password with SHA384 then using the OpenBSD BCrypt scheme and a salt generated by
            ///     <see cref="BCrypt.GenerateSalt()" />.
            /// </summary>
            /// <param name="inputKey">The password to hash.</param>
            /// <param name="workFactor">Defaults to 11</param>
            /// <param name="hashType">Configurable hash type for enhanced entropy</param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string EnhancedHashPassword(string inputKey, HashType hashType, int workFactor = DefaultRounds) =>
                HashPassword(inputKey, GenerateSalt(workFactor), true, hashType);

            /// <summary>
            ///     Hash a password using the OpenBSD BCrypt scheme and a salt generated by
            ///     <see cref="BCrypt.GenerateSalt(int,char)" /> using the given <paramref name="workFactor" />.
            /// </summary>
            /// <param name="inputKey">     The password to hash.</param>
            /// <param name="workFactor">
            ///     The log2 of the number of rounds of hashing to apply - the work
            ///     factor therefore increases as 2^workFactor. Default is 11
            /// </param>
            /// <param name="enhancedEntropy">
            ///     Set to true,the string will undergo SHA384 hashing to make use of available entropy prior
            ///     to bcrypt hashing
            /// </param>
            /// <returns>The hashed password.</returns>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static string HashPassword(string inputKey, int workFactor, bool enhancedEntropy = false) =>
                HashPassword(inputKey, GenerateSalt(workFactor), enhancedEntropy);

            /// <summary>Hash a password using the OpenBSD BCrypt scheme.</summary>
            /// <exception cref="ArgumentException">Thrown when one or more arguments have unsupported or illegal values.</exception>
            /// <param name="inputKey">The password or string to hash.</param>
            /// <param name="salt">    the salt to hash with (best generated using <see cref="BCrypt.GenerateSalt()" />).</param>
            /// <returns>The hashed password</returns>
            /// <exception cref="SaltParseException">Thrown when the <paramref name="salt" /> could not be parsed.</exception>
            public static string HashPassword(string inputKey, string salt) => HashPassword(inputKey, salt, false);

            /// <summary>Hash a password using the OpenBSD BCrypt scheme.</summary>
            /// <exception cref="ArgumentException">Thrown when one or more arguments have unsupported or illegal values.</exception>
            /// <param name="inputKey">The password or string to hash.</param>
            /// <param name="salt">    the salt to hash with (best generated using <see cref="BCrypt.GenerateSalt()" />).</param>
            /// <param name="enhancedEntropy">
            ///     Set to true,the string will undergo hashing (defaults to SHA384 then base64 encoding) to
            ///     make use of available entropy prior to bcrypt hashing
            /// </param>
            /// <param name="hashType">Configurable hash type for enhanced entropy</param>
            /// <returns>The hashed password</returns>
            /// <exception cref="ArgumentNullException">Thrown when the <paramref name="inputKey" /> is null.</exception>
            /// <exception cref="SaltParseException">Thrown when the <paramref name="salt" /> could not be parsed.</exception>
            public static string HashPassword(string inputKey, string salt, bool enhancedEntropy,
                HashType hashType = DefaultEnhancedHashType)
            {
                if (inputKey == null)
                {
                    throw new ArgumentNullException(nameof(inputKey));
                }

                if (string.IsNullOrEmpty(salt))
                {
                    throw new ArgumentException("Invalid salt: salt cannot be null or empty", nameof(salt));
                }

                if (enhancedEntropy && hashType == HashType.None)
                {
                    throw new ArgumentException(
                        "Invalid HashType, You can't have an enhanced hash with type none. HashType.None is used for internal clarity only.",
                        nameof(hashType));
                }

                // Determine the starting offset and validate the salt
                int startingOffset;
                char minor = (char)0;
                if (salt[0] != '$' || salt[1] != '2')
                {
                    throw new SaltParseException("Invalid salt version");
                }

                if (salt[2] == '$')
                {
                    startingOffset = 3;
                }
                else
                {
                    minor = salt[2];
                    if (minor != 'a' && minor != 'b' && minor != 'x' && minor != 'y' || salt[3] != '$')
                    {
                        throw new SaltParseException("Invalid salt revision");
                    }

                    startingOffset = 4;
                }

                // Extract number of rounds
                if (salt[startingOffset + 2] > '$')
                {
                    throw new SaltParseException("Missing salt rounds");
                }

                // Extract details from salt
                int workFactor = Convert.ToInt16(salt.Substring(startingOffset, 2));

                // Throw if log rounds are out of range on hash, deals with custom salts
                if (workFactor < 1 || workFactor > 31)
                {
                    throw new SaltParseException("Salt rounds out of range");
                }

                string extractedSalt = salt.Substring(startingOffset + 3, 22);

                byte[] inputBytes = SafeUTF8.GetBytes(inputKey + (minor >= 'a' ? Nul : EmptyString));

                if (enhancedEntropy)
                {
                    inputBytes = EnhancedHash(inputBytes, hashType);
                }

                byte[] saltBytes = DecodeBase64(extractedSalt, BCryptSaltLen);

                BCrypt bCrypt = new BCrypt();

                byte[] hashed = bCrypt.CryptRaw(inputBytes, saltBytes, workFactor);

                // Generate result string
                StringBuilder result = new StringBuilder();
                result.AppendFormat("$2{1}${0:00}$", workFactor, minor);
                result.Append(EncodeBase64(saltBytes, saltBytes.Length));
                result.Append(EncodeBase64(hashed, (BfCryptCiphertext.Length * 4) - 1));

                return result.ToString();
            }

            /// <summary>
            ///     Hashes key, base64 encodes before returning byte array
            /// </summary>
            /// <param name="inputBytes"></param>
            /// <param name="hashType"></param>
            /// <returns></returns>
            private static byte[] EnhancedHash(byte[] inputBytes, HashType hashType)
            {
                switch (hashType)
                {
                    case HashType.SHA256:
                        inputBytes = SafeUTF8.GetBytes(Convert.ToBase64String(SHA256.Create().ComputeHash(inputBytes)));
                        break;
                    case HashType.SHA384:
                        inputBytes = SafeUTF8.GetBytes(Convert.ToBase64String(SHA384.Create().ComputeHash(inputBytes)));
                        break;
                    case HashType.SHA512:
                        inputBytes = SafeUTF8.GetBytes(Convert.ToBase64String(SHA512.Create().ComputeHash(inputBytes)));
                        break;
                    case HashType.Legacy384:
                        inputBytes = SHA384.Create().ComputeHash(inputBytes);
                        break;
                    default:
                        throw new ArgumentOutOfRangeException(nameof(hashType), hashType, null);
                }

                return inputBytes;
            }


            /// <summary>
            ///     Generate a salt for use with the <see cref="BCrypt.HashPassword(string, string)" /> method.
            /// </summary>
            /// <param name="workFactor">
            ///     The log2 of the number of rounds of hashing to apply - the work
            ///     factor therefore increases as 2**workFactor.
            /// </param>
            /// <param name="bcryptMinorRevision"></param>
            /// <exception cref="ArgumentOutOfRangeException">Work factor must be between 4 and 31</exception>
            /// <returns>A base64 encoded salt value.</returns>
            /// <exception cref="ArgumentException">BCrypt Revision should be a, b, x or y</exception>
            public static string GenerateSalt(int workFactor, char bcryptMinorRevision = DefaultHashVersion)
            {
                if (workFactor < MinRounds || workFactor > MaxRounds)
                {
                    throw new ArgumentOutOfRangeException(nameof(workFactor), workFactor,
                        $"The work factor must be between {MinRounds} and {MaxRounds} (inclusive)");
                }

                if (bcryptMinorRevision != 'a' && bcryptMinorRevision != 'b' && bcryptMinorRevision != 'x' &&
                    bcryptMinorRevision != 'y')
                {
                    throw new ArgumentException("BCrypt Revision should be a, b, x or y", nameof(bcryptMinorRevision));
                }

                byte[] saltBytes = new byte[BCryptSaltLen];

                RngCsp.GetBytes(saltBytes);

                StringBuilder result = new StringBuilder();
                result.AppendFormat("$2{1}${0:00}$", workFactor, bcryptMinorRevision);
                result.Append(EncodeBase64(saltBytes, saltBytes.Length));
                return result.ToString();
            }


            /// <summary>
            ///     Based on password_needs_rehash in PHP this method will return true
            ///     if the work factor (logrounds) set on the hash is lower than the new minimum workload passed in
            /// </summary>
            /// <param name="hash">full bcrypt hash</param>
            /// <param name="newMinimumWorkLoad">target workload</param>
            /// <returns>true if new work factor is higher than the one in the hash</returns>
            /// <exception cref="ArgumentException">throws if the current hash workload (logrounds) can not be parsed</exception>
            /// <exception cref="HashInformationException"></exception>
            public static bool PasswordNeedsRehash(string hash, int newMinimumWorkLoad)
            {
                var hashInfo = InterrogateHash(hash);
                int currentWorkLoad;
                if (!Int32.TryParse(hashInfo.WorkFactor, out currentWorkLoad))
                {
                    throw new ArgumentException("Work Factor (logrounds) could not be parsed", nameof(hash));
                }

                return currentWorkLoad < newMinimumWorkLoad;
            }

            private static readonly TimeSpan RegexTimeout = TimeSpan.FromMilliseconds(30);

            private static readonly Regex HashInformation =
                new Regex(@"^(?<settings>\$2[a-z]{1}?\$\d\d?)\$(?<hash>[A-Za-z0-9\./]{53})$", RegexOptions.Singleline,
                    RegexTimeout);

            private static readonly Regex SettingsInformation = new Regex(@"^\$(?<version>2[a-z]{1}?)\$(?<rounds>\d\d?)$",
                RegexOptions.Singleline, RegexTimeout);

            /// <summary>
            ///     Takes a valid hash and outputs its component parts
            /// </summary>
            /// <param name="hash"></param>
            /// <exception cref="HashInformationException"></exception>
            public static HashInformation InterrogateHash(string hash)
            {
                try
                {
                    var hashInfo = HashInformation.Match(hash);

                    if (!hashInfo.Success)
                    {
                        throw new SaltParseException("Invalid Hash Format");
                    }

                    var saltInfo = SettingsInformation.Match(hashInfo.Groups["settings"].Value);
                    if (!saltInfo.Success)
                    {
                        throw new SaltParseException("Invalid Settings Format");
                    }

                    return new HashInformation(hashInfo.Groups["settings"].Value,
                        saltInfo.Groups["version"].Value,
                        saltInfo.Groups["rounds"].Value,
                        hashInfo.Groups["hash"].Value);
                }
                catch (Exception ex)
                {
                    throw new HashInformationException("Error handling string interrogation", ex);
                }
            }


            /// <summary>
            ///     Generate a salt for use with the <see cref="BCrypt.HashPassword(string,string)" /> method
            ///     selecting a reasonable default for the number of hashing rounds to apply.
            /// </summary>
            /// <returns>A base64 encoded salt value.</returns>
            public static string GenerateSalt()
            {
                return GenerateSalt(DefaultRounds);
            }

            /// <summary>
            ///     Verifies that the hash of the given <paramref name="text" /> matches the provided
            ///     <paramref name="hash" />; the string will undergo SHA384 hashing to maintain the enhanced entropy work done during
            ///     hashing
            /// </summary>
            /// <param name="text">The text to verify.</param>
            /// <param name="hash"> The previously-hashed password.</param>
            /// <param name="hashType">HashType used (default SHA384)</param>
            /// <returns>true if the passwords match, false otherwise.</returns>
            public static bool EnhancedVerify(string text, string hash, HashType hashType = DefaultEnhancedHashType) =>
                Verify(text, hash, true, hashType);

            /// <summary>
            ///     Verifies that the hash of the given <paramref name="text" /> matches the provided
            ///     <paramref name="hash" />
            /// </summary>
            /// <param name="text">The text to verify.</param>
            /// <param name="hash"> The previously-hashed password.</param>
            /// <param name="enhancedEntropy">
            ///     Set to true,the string will undergo SHA384 hashing to make use of available entropy prior
            ///     to bcrypt hashing
            /// </param>
            /// <param name="hashType">HashType used (default SHA384)</param>
            /// <returns>true if the passwords match, false otherwise.</returns>
            /// <exception cref="ArgumentException">Thrown when one or more arguments have unsupported or illegal values.</exception>
            /// <exception cref="SaltParseException">Thrown when the salt could not be parsed.</exception>
            public static bool Verify(string text, string hash, bool enhancedEntropy = false,
                HashType hashType = DefaultEnhancedHashType)
            {
                return SecureEquals(SafeUTF8.GetBytes(hash),
                    SafeUTF8.GetBytes(HashPassword(text, hash, enhancedEntropy, hashType)));
            }

            // Compares two byte arrays for equality. The method is specifically written so that the loop is not optimised.
            [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
            private static bool SecureEquals(byte[] a, byte[] b)
            {
                if (a == null && b == null)
                {
                    return true;
                }

                if (a == null || b == null || a.Length != b.Length)
                {
                    return false;
                }

                int diff = 0;
                for (var i = 0; i < a.Length; i++)
                {
                    diff |= (a[i] ^ b[i]);
                }

                return diff == 0;
            }


            /// <summary>
            ///     Encode a byte array using BCrypt's slightly-modified base64 encoding scheme. Note that this
            ///     is *not* compatible with the standard MIME-base64 encoding.
            /// </summary>
            /// <exception cref="ArgumentException">
            ///     Thrown when one or more arguments have unsupported or
            ///     illegal values.
            /// </exception>
            /// <param name="byteArray">The byte array to encode.</param>
            /// <param name="length">   The number of bytes to encode.</param>
            /// <returns>Base64-encoded string.</returns>
            private static string EncodeBase64(byte[] byteArray, int length)
            {
                if (length <= 0 || length > byteArray.Length)
                {
                    throw new ArgumentException("Invalid length", nameof(length));
                }

                int off = 0;
                StringBuilder rs = new StringBuilder();
                while (off < length)
                {
                    int c1 = byteArray[off++] & 0xff;
                    rs.Append(Base64Code[(c1 >> 2) & 0x3f]);
                    c1 = (c1 & 0x03) << 4;
                    if (off >= length)
                    {
                        rs.Append(Base64Code[c1 & 0x3f]);
                        break;
                    }

                    int c2 = byteArray[off++] & 0xff;
                    c1 |= (c2 >> 4) & 0x0f;
                    rs.Append(Base64Code[c1 & 0x3f]);
                    c1 = (c2 & 0x0f) << 2;
                    if (off >= length)
                    {
                        rs.Append(Base64Code[c1 & 0x3f]);
                        break;
                    }

                    c2 = byteArray[off++] & 0xff;
                    c1 |= (c2 >> 6) & 0x03;
                    rs.Append(Base64Code[c1 & 0x3f]);
                    rs.Append(Base64Code[c2 & 0x3f]);
                }

                return rs.ToString();
            }

            /// <summary>
            ///     Decode a string encoded using BCrypt's base64 scheme to a byte array.
            ///     Note that this is *not* compatible with the standard MIME-base64 encoding.
            /// </summary>
            /// <exception cref="ArgumentException">
            ///     Thrown when one or more arguments have unsupported or
            ///     illegal values.
            /// </exception>
            /// <param name="encodedstring">The string to decode.</param>
            /// <param name="maximumBytes"> The maximum bytes to decode.</param>
            /// <returns>The decoded byte array.</returns>
            internal static byte[] DecodeBase64(string encodedstring, int maximumBytes)
            {
                int position = 0;
                int sourceLength = encodedstring.Length;
                int outputLength = 0;

                if (maximumBytes <= 0)
                {
                    throw new ArgumentException("Invalid maximum bytes value", nameof(maximumBytes));
                }

                StringBuilder rs = new StringBuilder();
                while (position < sourceLength - 1 && outputLength < maximumBytes)
                {
                    int c1 = Char64(encodedstring[position++]);
                    int c2 = Char64(encodedstring[position++]);
                    if (c1 == -1 || c2 == -1)
                    {
                        break;
                    }

                    rs.Append((char)((c1 << 2) | ((c2 & 0x30) >> 4)));
                    if (++outputLength >= maximumBytes || position >= sourceLength)
                    {
                        break;
                    }

                    int c3 = Char64(encodedstring[position++]);
                    if (c3 == -1)
                    {
                        break;
                    }

                    rs.Append((char)(((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2)));
                    if (++outputLength >= maximumBytes || position >= sourceLength)
                    {
                        break;
                    }

                    int c4 = Char64(encodedstring[position++]);
                    rs.Append((char)(((c3 & 0x03) << 6) | c4));

                    ++outputLength;
                }

                byte[] ret = new byte[outputLength];
                for (position = 0; position < outputLength; position++)
                {
                    ret[position] = (byte)rs[position];
                }

                return ret;
            }

            /// <summary>
            ///     Look up the 3 bits base64-encoded by the specified character, range-checking against
            ///     conversion table.
            /// </summary>
            /// <param name="character">The base64-encoded value.</param>
            /// <returns>The decoded value of x.</returns>
            private static int Char64(char character)
            {
                return character < 0 || character > Index64.Length ? -1 : Index64[character];
            }

            /// <summary>Blowfish encipher a single 64-bit block encoded as two 32-bit halves.</summary>
            /// <param name="blockArray">An array containing the two 32-bit half blocks.</param>
            /// <param name="offset">    The position in the array of the blocks.</param>
            private void Encipher(uint[] blockArray, int offset)
            {
                uint block = blockArray[offset];
                uint r = blockArray[offset + 1];

                block ^= _p[0];

                unchecked
                {
                    uint round;
                    for (round = 0; round <= BlowfishNumRounds - 2;)
                    {
                        // Feistel substitution on left word
                        uint n = _s[(block >> 24) & 0xff];
                        n += _s[0x100 | ((block >> 16) & 0xff)];
                        n ^= _s[0x200 | ((block >> 8) & 0xff)];
                        n += _s[0x300 | (block & 0xff)];
                        r ^= n ^ _p[++round];

                        // Feistel substitution on right word
                        n = _s[(r >> 24) & 0xff];
                        n += _s[0x100 | ((r >> 16) & 0xff)];
                        n ^= _s[0x200 | ((r >> 8) & 0xff)];
                        n += _s[0x300 | (r & 0xff)];
                        block ^= n ^ _p[++round];
                    }

                    blockArray[offset] = r ^ _p[BlowfishNumRounds + 1];
                    blockArray[offset + 1] = block;
                }
            }

            /// <summary>Cyclically extract a word of key material.</summary>
            /// <param name="data">The string to extract the data from.</param>
            /// <param name="offset"> [in,out] The current offset.</param>
            /// <returns>The next word of material from data.</returns>
            private static uint StreamToWord(byte[] data, ref int offset)
            {
                int i;
                uint word = 0;

                for (i = 0; i < 4; i++)
                {
                    word = (word << 8) | (uint)(data[offset] & 0xff);
                    offset = (offset + 1) % data.Length;
                }

                return word;
            }

            /// <summary>Initializes the Blowfish key schedule.</summary>
            private void InitializeKey()
            {
                _p = new uint[POrig.Length];
                _s = new uint[SOrig.Length];
                Array.Copy(POrig, _p, POrig.Length);
                Array.Copy(SOrig, _s, SOrig.Length);
            }

            /// <summary>Key the Blowfish cipher.</summary>
            /// <param name="keyBytes">The key byte array.</param>
            private void Key(byte[] keyBytes)
            {
                int i;
                int koffp = 0;
                uint[] lr = { 0, 0 };
                int plen = _p.Length, slen = _s.Length;

                for (i = 0; i < plen; i++)
                {
                    _p[i] = _p[i] ^ StreamToWord(keyBytes, ref koffp);
                }

                for (i = 0; i < plen; i += 2)
                {
                    Encipher(lr, 0);
                    _p[i] = lr[0];
                    _p[i + 1] = lr[1];
                }

                for (i = 0; i < slen; i += 2)
                {
                    Encipher(lr, 0);
                    _s[i] = lr[0];
                    _s[i + 1] = lr[1];
                }
            }

            /// <summary>
            ///     Perform the "enhanced key schedule" step described by Provos and Mazieres in
            ///     "A Future Adaptable Password Scheme" http://www.openbsd.org/papers/bcrypt-paper.ps.
            /// </summary>
            /// <param name="saltBytes"> Salt byte array.</param>
            /// <param name="inputBytes">Input byte array.</param>
            // ReSharper disable once InconsistentNaming
            private void EKSKey(byte[] saltBytes, byte[] inputBytes)
            {
                int i;
                int passwordOffset = 0;
                int saltOffset = 0;
                uint[] lr = { 0, 0 };
                int plen = _p.Length, slen = _s.Length;

                for (i = 0; i < plen; i++)
                {
                    _p[i] = _p[i] ^ StreamToWord(inputBytes, ref passwordOffset);
                }

                for (i = 0; i < plen; i += 2)
                {
                    lr[0] ^= StreamToWord(saltBytes, ref saltOffset);
                    lr[1] ^= StreamToWord(saltBytes, ref saltOffset);
                    Encipher(lr, 0);
                    _p[i] = lr[0];
                    _p[i + 1] = lr[1];
                }

                for (i = 0; i < slen; i += 2)
                {
                    lr[0] ^= StreamToWord(saltBytes, ref saltOffset);
                    lr[1] ^= StreamToWord(saltBytes, ref saltOffset);
                    Encipher(lr, 0);
                    _s[i] = lr[0];
                    _s[i + 1] = lr[1];
                }
            }

            /// <summary>Perform the central hashing step in the BCrypt scheme.</summary>
            /// <exception cref="ArgumentException">
            ///     Thrown when one or more arguments have unsupported or
            ///     illegal values.
            /// </exception>
            /// <param name="inputBytes">The input byte array to hash.</param>
            /// <param name="saltBytes"> The salt byte array to hash with.</param>
            /// <param name="workFactor"> The binary logarithm of the number of rounds of hashing to apply.</param>
            /// <returns>A byte array containing the hashed result.</returns>
            internal byte[] CryptRaw(byte[] inputBytes, byte[] saltBytes, int workFactor)
            {
                int i;
                int j;

                uint[] cdata = new uint[BfCryptCiphertext.Length];
                Array.Copy(BfCryptCiphertext, cdata, BfCryptCiphertext.Length);
                int clen = cdata.Length;

                if (workFactor < MinRounds || workFactor > MaxRounds)
                {
                    throw new ArgumentException("Bad number of rounds", nameof(workFactor));
                }

                if (saltBytes.Length != BCryptSaltLen)
                {
                    throw new ArgumentException("Bad salt Length", nameof(saltBytes));
                }

                uint rounds = 1u << workFactor;

                // We overflowed rounds at 31 - added safety check
                if (rounds < 1)
                {
                    throw new ArgumentException("Bad number of rounds", nameof(workFactor));
                }

                InitializeKey();
                EKSKey(saltBytes, inputBytes);

                for (i = 0; i != rounds; i++)
                {
                    Key(inputBytes);
                    Key(saltBytes);
                }

                for (i = 0; i < 64; i++)
                {
                    for (j = 0; j < (clen >> 1); j++)
                    {
                        Encipher(cdata, j << 1);
                    }
                }

                byte[] ret = new byte[clen * 4];
                for (i = 0, j = 0; i < clen; i++)
                {
                    ret[j++] = (byte)((cdata[i] >> 24) & 0xff);
                    ret[j++] = (byte)((cdata[i] >> 16) & 0xff);
                    ret[j++] = (byte)((cdata[i] >> 8) & 0xff);
                    ret[j++] = (byte)(cdata[i] & 0xff);
                }

                return ret;
            }
        }
    }
}
